Project Summary This R21 application proposes the development and pilot evaluation of a clinically-based, technology- augmented secondary prevention intervention for adolescent victims of cyber-bullying. Approximately 25% of adolescents (age 13-17) report past-year cyber-victimization. Cyber-victimization correlates with numerous negative long-term psychosocial effects, including suicidality, depression, and substance use. Pediatricians currently provide in-clinic preventive interventions to adolescents on a variety of topics. They have been encouraged to screen and counsel adolescents on cyber-victimization; however, no effective cyber- victimization prevention interventions exist for the clinical setting. Brief in-person interventions and longitudinal text-message interventions are acceptable, feasible, and effective at changing adolescent behaviors, including those related to occurrence of physical victimization. Drawing on prior work, this application proposes using a rigorous two-step process to develop an intervention consisting of a brief in-clinic cyber-victimization prevention session, followed by an eight-week tailored, two-way text-messaging program. The two-part intervention will focus on (a) enhancing participants' self-efficacy and resetting norms regarding cyber- victimization and (b) improving participants' emotional regulation and cognitive restructuring in the face of cyber-victimization. In Aim 1, the novel intervention will be developed based on social cognitive learning theory, prior work by the research team, semi-structured interviews with adolescents, and an iterative refinement process during a series of open pilot tests. In Aim 2, the feasibility and acceptability of the novel in- clinic + text-message intervention will be assessed through a pilot randomized controlled trial (n=50). Additionally, the study team will establish the feasibility of an innovative method for measuring cyber- victimization, downloading participants' anonymized social interactions directly from their phones using a previously-piloted computer program, and developing preliminary coding schemes to identify victimization. If the intervention is shown feasible and effective, this study is expected to inform a future large scale effectiveness study to embed a technology-augmented intervention in the clinical setting. The proposed intervention would have broad public health implications, giving clinicians a much-needed tool to reduce cyber- victimization and its consequences in adolescents, addressing both NICHD Vision Themes and critical adolescent objectives of Healthy People 2020.